fix grid opacity not updating live

wayvr/src/backend/openxr/helpers.rs

@@ -3,6 +3,18 @@ use glam::{Affine3A, Quat, Vec3, Vec3A};
 use openxr::{self as xr, SessionCreateFlags, Version, sys::Handle};
 use xr::OverlaySessionCreateFlagsEXTX;
 
+macro_rules! next_chain_insert {
+    ($layer:expr, $payload:expr) => {{
+        let payload_ptr = $payload as *mut _ as *mut xr::sys::BaseInStructure;
+        let new_elem = payload_ptr.as_mut().unwrap();
+        let mut raw = $layer.into_raw();
+        new_elem.next = raw.next as _;
+        raw.next = payload_ptr as *const _;
+        raw
+    }};
+}
+pub(crate) use next_chain_insert;
+
 pub(super) fn init_xr() -> Result<(xr::Instance, xr::SystemId), anyhow::Error> {
     let entry = xr::Entry::linked();
 

wayvr/src/backend/openxr/overlay.rs

@@ -6,7 +6,10 @@ use xr::EyeVisibility;
 
 use super::{CompositionLayer, XrState, helpers, swapchain::WlxSwapchain};
 use crate::{
-    backend::openxr::swapchain::{SwapchainOpts, WlxSwapchainImage, create_swapchain},
+    backend::openxr::{
+        helpers::next_chain_insert,
+        swapchain::{SwapchainOpts, WlxSwapchainImage, create_swapchain},
+    },
     state::AppState,
     windowing::window::OverlayWindowData,
 };
@@ -20,17 +23,6 @@ pub struct OpenXrOverlayData {
     color_bias_khr: Option<Box<xr::sys::CompositionLayerColorScaleBiasKHR>>,
 }
 
-macro_rules! next_chain_insert {
-    ($layer:expr, $payload:expr) => {{
-        let payload_ptr = $payload.as_mut() as *mut _ as *mut xr::sys::BaseInStructure;
-        let new_elem = payload_ptr.as_mut().unwrap();
-        let mut raw = $layer.into_raw();
-        new_elem.next = raw.next as _;
-        raw.next = payload_ptr as *const _;
-        raw
-    }};
-}
-
 impl OverlayWindowData<OpenXrOverlayData> {
     pub(super) fn ensure_swapchain_acquire<'a>(
         &'a mut self,

wayvr/src/backend/openxr/skybox.rs

@@ -14,7 +14,10 @@ use wgui::gfx::{cmd::WGfxClearMode, pipeline::WPipelineCreateInfo};
 use wlx_common::config_io;
 
 use crate::{
-    backend::openxr::{helpers::translation_rotation_to_posef, swapchain::SwapchainOpts},
+    backend::openxr::{
+        helpers::{next_chain_insert, translation_rotation_to_posef},
+        swapchain::SwapchainOpts,
+    },
     graphics::{ExtentExt, GpuFutures, dds::WlxCommandBufferDds},
     state::AppState,
 };
@@ -28,10 +31,11 @@ pub(super) struct Skybox {
     view: Arc<ImageView>,
     sky: Option<WlxSwapchain>,
     grid: Option<WlxSwapchain>,
+    grid_color_scale_bias_khr: Option<xr::sys::CompositionLayerColorScaleBiasKHR>,
 }
 
 impl Skybox {
-    pub fn new(app: &AppState) -> anyhow::Result<Self> {
+    pub fn new(xr: &XrState, app: &AppState) -> anyhow::Result<Self> {
         let mut command_buffer = app
             .gfx
             .create_xfer_command_buffer(CommandBufferUsage::OneTimeSubmit)?;
@@ -74,10 +78,27 @@ impl Skybox {
 
         let view = ImageView::new_default(maybe_image.unwrap())?; // safe unwrap
 
+        let grid_color_scale_bias_khr = xr
+            .instance
+            .exts()
+            .khr_composition_layer_color_scale_bias
+            .map(|_| xr::sys::CompositionLayerColorScaleBiasKHR {
+                ty: xr::StructureType::COMPOSITION_LAYER_COLOR_SCALE_BIAS_KHR,
+                next: std::ptr::null(),
+                color_bias: Default::default(),
+                color_scale: xr::Color4f {
+                    r: 1.0,
+                    g: 1.0,
+                    b: 1.0,
+                    a: 1.0,
+                },
+            });
+
         Ok(Self {
             view,
             sky: None,
             grid: None,
+            grid_color_scale_bias_khr: grid_color_scale_bias_khr,
         })
     }
 
@@ -161,17 +182,13 @@ impl Skybox {
             .into_iter()
             .next()
             .unwrap();
-        let set0 = pipeline.uniform_buffer_upload(
-            0,
-            vec![app.session.config.grid_opacity * app.session.config.grid_opacity],
-        )?;
         let pass = pipeline.create_pass(
             tgt.extent_f32(),
             [0.0, 0.0],
             app.gfx_extras.quad_verts.clone(),
             0..4,
             0..1,
-            vec![set0],
+            vec![],
             &Default::default(),
         )?;
 
@@ -236,8 +253,10 @@ impl Skybox {
             .lower_vertical_angle(LO_VERT_ANGLE);
 
         self.grid.as_mut().unwrap().ensure_image_released()?;
-        let grid = xr::CompositionLayerQuad::new()
+        let flags = xr::CompositionLayerFlags::BLEND_TEXTURE_SOURCE_ALPHA
-            .layer_flags(xr::CompositionLayerFlags::BLEND_TEXTURE_SOURCE_ALPHA)
+            | xr::CompositionLayerFlags::UNPREMULTIPLIED_ALPHA;
+        let mut grid = xr::CompositionLayerQuad::new()
+            .layer_flags(flags)
             .pose(*GRID_POSE)
             .size(xr::Extent2Df {
                 width: 10.0,
@@ -247,6 +266,15 @@ impl Skybox {
             .eye_visibility(xr::EyeVisibility::BOTH)
             .space(&xr.stage);
 
+        if let Some(grid_color_scale_bias_khr) = self.grid_color_scale_bias_khr.as_mut() {
+            let grid_opacity = app.session.config.grid_opacity;
+            grid_color_scale_bias_khr.color_scale.a = grid_opacity * grid_opacity;
+            unsafe {
+                let raw = next_chain_insert!(grid, grid_color_scale_bias_khr);
+                grid = xr::CompositionLayerQuad::from_raw(raw);
+            }
+        }
+
         Ok(vec![
             CompositionLayer::Equirect2(sky),
             CompositionLayer::Quad(grid),
@@ -258,5 +286,5 @@ pub(super) fn create_skybox(xr: &XrState, app: &AppState) -> Option<Skybox> {
     xr.instance
         .exts()
         .khr_composition_layer_equirect2
-        .and_then(|_| Skybox::new(app).ok())
+        .and_then(|_| Skybox::new(xr, app).ok())
 }

wayvr/src/shaders/grid.frag

@@ -4,10 +4,6 @@ precision highp float;
 layout (location = 0) in vec2 in_uv;
 layout (location = 0) out vec4 out_color;
 
-layout (set = 0, binding = 0) uniform OpacityBlock {
-    uniform float opacity;
-};
-
 void main()
 {
     float fade = max(1.0 - 2.0 * length(in_uv.xy + vec2(-0.5, -0.5)), 0.0);
@@ -18,6 +14,5 @@ void main()
     } else {
         grid = 0.0;
     }
-    out_color = vec4(1.0, 1.0, 1.0, grid * fade * opacity);
+    out_color = vec4(1.0, 1.0, 1.0, grid * fade);
 }
-